Cassini readies final plunge into Saturn

NASA's Cassini probe is counting its final hours before one last plunge into Saturn on Friday that will cap a fruitful 13-year mission that greatly expanded knowledge about the gas giant.While orbiting Saturn nearly 300 times, Cassini made major discoveries, such as the liquid methane seas of the planet's giant moon Titan and the sprawling subsurface ocean of Enceladus, a small Saturn moon."Cassini-Huygens is an extraordinary mission of discovery that has revolutionized our understanding of the